Deliberate mistake: Has there ever been a more obvious body double than the one used for Angie Dickinson in the shower scene? Not only does the top of every shot stop right at the collarbones, she is much taller than Dickinson, she has a much deeper tan and (of course) her breasts are much, much bigger. In fact that is Victoria Johnson, Penthouse Pet of the Month for August, 1976.
Deliberate mistake: When Jamie Lee is picked up hitch hiking, the view out the front windshield, while pulling over to pick her up, is identical when they pull over moments later after all the windows are shattering.
Deliberate mistake: When they are playing strip monopoly, Alice purchases Baltic Avenue and then Bill rolls the dice and Alice exclaims that he's rolled an "8" - putting him on Baltic Avenue. However if you look carefully at the dice (before Brenda quickly scoops them up) you can see they show two 5's. (00:40:05)